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Re: Intake Air Temp

I believe Jay is right about the Intake air Temp having a significant 
difference for any matter...

People at the races tell me every 10F is 1hp. If you have temperatures 
100+ under the hood (which its probably more) compared to outside air
you're at a loss of about 10hp's. 10horses is equivalent to what about 
most chip manufacturers claim their chips produce. Well, then a 10hp 
loss would make a noticable difference, even for normal driving. That's 
why even a ram-air intake makes some difference...I've seen it on a 
friends 325is.

I guess that's why people sometimes remove their headlight during 
competition events to gain that extra edge. But to say that the  
difference in under hood temps vs. outside air for normal driving being 
irrelivant is ignorant.

Ruell-
1995 318ti
- -------original message-------------------------
From: Jay Snyder <jay.snyder@domain.elided>
Date: Thu, 19 Sep 1996 08:38:04 -0400
Subject: Intake Air Temp

You mention seem to think that 180F vs. 80F isn't a significant 
difference in
air density.  I beg to differ.  Ask any airplane pilot about take-off 
and
climb performance of his airplane on a 90F day vs. a 60F day.  It is
significant.

The following is taken from the specs on the Lycoming O-360 in my Piper
Archer II (airplane, these are 70~75% cruise power settings, the peak 
power
of this engine
is 180HP @ 2700RPM -- can you say Torque!):

OS TMP  HP @2400RPM Sea Level
100F    126HP
80F     130HP
60F     135HP

40F differnece makes a 7% difference in available HP (and torque), so 
the
100F difference you speak of is more significant than that.